Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int A[105][105];
int R[105], C[105];
int mini = 0, ans;
int n, m;
bool flip = 0;
int main() {
  cin.tie(NULL);
  ios::sync_with_stdio(0);
  cin >> n >> m;
  bool fail = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) cin >> A[i][j];
  if (m > n) {
    for (int i = 0; i < 100; i++)
      for (int j = 0; j < 100; j++)
        if (i > j) swap(A[i][j], A[j][i]);
    swap(m, n);
    flip = 1;
  }
  for (int i = 0; i < m; i++) {
    C[i] = A[0][i];
  }
  for (int i = 0; i < n; i++) {
    R[i] = A[i][0] - C[0];
    mini = min(mini, R[i]);
  }
  for (int i = 0; i < n; i++) {
    R[i] -= mini;
    ans += R[i];
  }
  for (int i = 0; i < m; i++) {
    C[i] += mini;
    ans += C[i];
    if (C[i] < 0) fail = 1;
  }
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      if (A[i][j] != R[i] + C[j]) fail = 1;
  if (!fail) {
    if (flip) {
      for (int i = 0; i < 100; i++)
        for (int j = 0; j < 100; j++)
          if (i > j) swap(A[i][j], A[j][i]);
      swap(m, n);
      for (int i = 0; i < 100; i++) swap(R[i], C[i]);
    }
    cout << ans << endl;
    for (int i = 0; i < n; i++)
      for (int j = 0; j < R[i]; j++) cout << "row " << i + 1 << endl;
    for (int i = 0; i < m; i++)
      for (int j = 0; j < C[i]; j++) cout << "col " << i + 1 << endl;
  } else
    cout << -1 << endl;
}